Yes, you can set any price you want on your chests. The minimum amount for 1 single chest is €1.99 (or $1.99). It's important to keep in mind that payment platforms take a fee from the total payment amount.
Paysafecard takes 15%, PayPal and credit card payments take $0.05 and 5%. Payment platform fees are external to Streamloots, so they could vary.